Agricultural belting

ABSTRACT

An improved agricultural belting (1) formed of multiple fabric by layers (2, 3 or 4), interposing rubber layers (5, 6) and rubber cover layers (7, 8). The fabric plies are a woven of warp yarns (10) extending in the longitudinal direction of the belt (1) and fill yarns (11) extending in the transverse direction of the belt (1). To optimize the transverse stiffness of the belting and other properties of the belt, any of the fabric plies (2, 3, or 4) are formed with selective replacement of the multifilament fill yarns (11) with monofilament cords (13). The fabric ply (2, 3, or 4) formed with monofilament cords (13) has at most fifty percent monofilament fill cords (13).

This application is a 371 of PCT/US98/14663 filed Jul. 21, 1998.

FIELD OF THE INVENTION

The disclosed invention is directed toward bale forming belts on roundhay balers. More specifically, the invention is a bale forming belt withan improved transverse stiffness and excellent fastener retention.

BACKGROUND OF THE INVENTION

This invention addresses the need to make the bale forming belts onround hay balers stiffer in the transverse direction. The increase intransverse stiffness counteracts the tendency of the belts to roll overon itself causing damage to the belt and shortening the service life ofthe belt. Also transversely stiff belts maintain their position on themachine when slack, i.e. very low tension, conditions occur during baleroperations. Increased transverse stiffness has long been recognized as adesirable feature in belts used on round hay balers. Manufacturers ofthese balers have historically advised belt producers of their desirefor improved transverse stiffness to enhance the operation of roundbalers.

Increased transverse stiffness must be achieved without a loss offastener retention. The belts must have excellent fastener holdingproperties, both as measured by static pull tests and by dynamic tests.The fastened ends of the belt represent the critical point formaintaining service life of the belt.

The increased transverse stiffness ideally should also be achieved incombination with optimized longitudinal flexibility. The hay balingbelts should have sufficient flexibility to enable the belts to runaround the relatively small pulleys of the hay baling machines.

The most effective method of increasing transverse stiffness is to useextruded monofilament cords of polyester, nylon, glass, or othermaterial in the outside plies of these multiply belts. The monofilamentcords are oriented in the transverse direction.

Current technology, as seen in U.S. Pat. No. 4,518,647, uses outsideplies that contain 100% monofilament fill cords. While this approachachieves dramatic transverse stiffness in the belt, there areshortcomings in the physical properties and cost of the belt.

Monofilament cords have lower tensile strength than comparable sizedtwisted multifilament cords. While a belt with 100% monofilament fillcords has dramatically high transverse stiffness, the tensile strengthof the belt is reduced. In addition, due to the extremely smooth outersurface of the monofilament, the cord has a limited adhesive dip pickup.

The disclosed belt construction has optimized properties of transversestiffness and tensile strength. The fastener holding capabilities, aswell as other physical properties, are maintained at a desired level.The inventive construction also keeps the cost increase, due to the useof monofilament cords, proportionate to the benefit gained in increasedtransverse stiffness, producing a more cost efficient product.

SUMMARY OF THE INVENTION

In accordance with the present invention, a belting material isdisclosed which has optimized transverse stiffness and improved fastenerholding capabilities.

In accordance with the disclosed invention, a multi-ply belting materialis disclosed wherein at least one woven ply has at most a fifty percentfill rate in the weft, or fill, direction of monofilament cords.

In a further aspect of the disclosed invention, the belting material isdisclosed with a minimum of five percent monofilament cords in the filldirection of the woven belting ply material.

In another aspect of the disclosed invention, the belting material isdisclosed wherein at least one woven ply has between five to fiftypercent extruded monofilament cords in the fill direction.

In accordance with another embodiment of the present invention, a threeply belting material is disclosed wherein the outermost woven plieshave, in the fill direction, at most fifty percent monofilament cords.

In accordance with another aspect of the present invention, beltingmaterial is disclosed which has optimized transverse stiffness, improvedfastener holding capabilities, and improved longitudinal flexibility.

In accordance with another embodiment of the present invention, atwo-ply belting is disclosed wherein both woven plies have at most, inthe fill direction, fifty percent monofilament cords.

In accordance with a further aspect of the invention, the two plybelting has a monofilament fill frequency of fifty to five percent.

DEFINITIONS

“Fabric” denotes a network of essentially unidirectionally extendingcord/yarns, which may be twisted, and which may in turn be composed of apluabty of a multiplicity of filaments (which may also be twisted). Thefabric is woven and flexible.

“Fill” refers to the cord/yarn woven at right angles to the warpcord/yarn or warp direction of the fabric.

“Warp” refers to a network of essentially unidirectionally extendingcords/yarns, which extend in the longitudinal direction of the belt.

“Weft” (filling) refers to the cord/yarn placed at right angles to thewarp cord/yarns.

“Yam”: a generic term for a continuous strand of textile fibers orfilaments. Yarn occurs in the following forms:

1) a number of fibers twisted together;

2) a number of filaments laid together without twist;

3) a number of filaments laid together with a degree of twist;

4) a single filament with or without twist (monofilament).

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be described by way of example and with reference tothe accompanying drawings in which:

FIG. 1 is a cut section of the inventive three ply belting;

FIG. 2 is a cross-sectional view of the outer fabric plies.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 illustrates a three ply belting 1 within the scope of the presentinvention. The belting has a first outer fabric ply 2, a second outerfabric ply 3, and an inner fabric ply 4. The is inner fabric ply 4 issubstantially centered in the belting 1. The fabric ply 4 is a wovensynthetic fabric. The selected materials are those conventionally usedin belting, such as polyester, nylon, and glass. The material isselected such that the center fabric ply has a modulus and flex fatiguelife less than the modulus and flex fatigue life of the outer fabricplies. Interposed between the fabric plies are rubber skim layers 5, 6.Outward of each outer fabric ply is an additional rubber cover layer 7,8. The length of the belting extends in the longitudinal direction ofthe belt, while the width of the belting extends in the transversedirection.

The outer plies 2,3 are made of a woven fabric. The fabric isillustrated in FIG. 2. Longitudinally extending warp yarns 10 areinterwoven with transverse fill yarns 11. The fill yarns 11 are apredetermined combination of multi-filament cords 12 and monofilamentcords 13. Illustrated is a monofilament cord fill frequency of one cordat every fourth fill location, yielding a woven fabric with atwenty-five percent fill rate of the monofilament cords. The frequencyof the monofilament cords is varied to achieve a measured amount oftransverse stiffness increase without adversely affecting the physicalproperties of the belt.

The fill frequency of the monofilament cord is within the range of fiftypercent to five percent of the fill yarns. The minimum fill ratio of themonofilament cord is limited by the desired transverse stiffness. Themaximum fill ratio of the monofilament cord is limited by maintaining adesired rubber adhesion characteristic and tensile strength of thefabric. When the monofilament cords are evenly spaced in the filldirection of the fabric, the monofilament cords are located every otherto every twelfth fill location.

The monofilament fill locations may also be a repeating series ofadjacent monofilament with a repeating series of multifilament fillcords. For example, two adjacent monofilaments cords are next to threeadjacent multifilament cords wherein for each length of belting fabric,the total fill frequency of the monofilament cords is not more thanfifty percent.

Due to the selective placement of the monofilament cord in the fabricply 2, the belting retains the needed fastener retention properties. Themonofilament fill frequency is varied to achieve a measured amount oftransverse stiffness increase without adversely affecting the physicalproperties of the current belt design. To achieve a desired physicaleffect, the fill frequency in the plies may even differ.

The monofilament cord may be formed from extruded monofilament cords ofpolyester, nylon, or glass. The diameter of the monofilament cord isselected to approximate the diameter of the multifilament yarn in orderto produce an even fabric. By way of a non-limiting example, when usingmultifilament yarns of 1260 den/3, the monofilament cord ideally has adiameter of 0.5 mm. Other monofilament diameters such as 0.9 mm and 0.7mm may also be employed.

The multifilament yarns in the fill direction are polyester, nylon, orglass yarns. The yarns in the warp direction of the fabric areconventional belting materials such as polyester, nylon, or glass.

After the fabric ply is formed with the desired combination ofmultifilament and monofilament cords, the fabric is treated for improvedrubber adhesion in accordance with conventional techniques, such as RFLdipping.

The present invention is also applicable for two ply belting. Oneembodiment of a two ply belt in accordance with the present inventionprovides for both plies to be of the disclosed inventive fabric. Analternative embodiment of the two ply belting incorporates only one plyof the monofilament reinforced fabric. The fabric plies, whether of theinventive fabric or conventional woven fabric of lower modulus, are eachprovided with a skim layer 5 or 6 positioned between the fabric pliesupon final assembly. Outward of each fabric ply is a rubber cover layer7, 8. If the belting is formed of a combination of conventional wovenfabric and the inventive fabric, the skim gauge on the conventional plymay be reduced to accommodate a required total thickness of the belt.

Comparison testing of a 2 ply belt made in accordance with the disclosedinvention, a conventional 3-ply belt, and a conventional 2 ply belt wasdone, and the results thereof are set forth in Table 1.

TABLE 1 3 ply 2 ply 2 ply Belt Design: Outer Plies - warp 100%  100%100% nylon polyester nylon Outer Plies - fill 100%  100% 75% nylonmonofil. nylon   25% monofil. Center Ply - warp 100% — — polyesterCenter Ply - fill 100% — — polyester Belt Physical Properties PlyAdhesion, lb. 45 76 77 Breaking Strength, 2,467 3,447 3,762 PIWElongation at 220 PIW 1.57%  3.51% 3.37% Elongation at 300 PIW 2.25% 4.67% 5.09% Transverse Tear, lb. 233 516 536 Longitudinal Tear, lb. 190501 445 Rip, lb. 483 1,222 982 uz,1/9 Fastener Holding: Clipper 4½ HT665 780 776 rectangular & PIW* Clipper - Mato U35, 1,922 2201 2,265 PIWDynamic Testing: Permanent Elongation  .49% 2.61% 3.28% Dynamic Modulus6,746 6,745 5,839 Belt Stiffness:** Longitudinal, lb. 2.19 .67 1.12Transverse, lb. 5.61 2.38 3.66 *fasteners straight out; belt does notfail **determined by a 3 point deflection test, lbs required for 1.5inches deflection

Ply Adhesion. The 77 lbs. of ply adhesion for the inventive belt versusthe 45 lbs. for the conventional 3 ply belt translates into longerservice life for the disclosed belt and counteracts ply separation alongthe belt edges. Substantially equivalent adhesion values for theinventive 2 ply belt and the conventional 2 ply demonstrates that withthe inventive belt, no ply adhesion properties are lost by the inclusionof the smaller percentage of monofilament cords.

Breaking Strength. Greater breaking strength is preferred for hay balingbelts. Higher breaking strengths aid in resisting damage from anyabusive service conditions. The breaking strength for the inventive beltis greater than for the conventional 2 or 3 ply belts.

Transverse Tear. When belts “break” or come apart during service, theusual mode of failure is transverse tear. The exemplary inventive use ofnylon yarns in the warp direction and the combination of nylon yarns andmonofilament cords result in transverse tear resistance more than doublethat for the conventional belting.

Longitudinal Tear and Rip. These two tests measure the ability of thebelt to withstand forces that rupture the belt and propagate the breaklongitudinally along the belt length. Such tears are primarily caused byrocks, sticks, and other such items being picked up and puncturing thebelt during baler operations. The inventive belt has values more thantwice that of the conventional 3-ply belt.

Fastener Holding. The disclosed belt exhibits higher pullout values thanthe conventional 3-ply belt, and values comparable to a conventional2-ply belt.

Longitudinal Stiffness. The inventive belt has longitudinal stiffnesshalf that of the conventional 3-ply belt. This longitudinal flexibility,i.e. lower longitudinal stiffness, is an important characteristic thathas been identified as essential for belt movement around the relativelysmall pulleys of the haybaling machines.

Transverse Stiffness. The inventive belt has a transverse stiffness 54%greater than the conventional 2-ply belt. While the inventive belt has atransverse stiffness less than that of the 3-ply belt, the greater tearproperties compensate for the stiffness.

The disclosed inventive belting achieves the objective of increasingtransverse properties while maintaining other necessary physicalproperties for good belt performance.

What is claimed is:
 1. An improved multiple ply belting (1) comprisingat least two fabric plies (2, 3, or 4) having fill cords (11) extendingin the transverse direction of the belt, a rubber layer (5, or 6)disposed between the fabric plies (2, 3, or 4), and outer coating rubberlayers (7, 8), the belting (1) being characterized by: at least one ofthe fabric plies (2, 3, or 4) having monofilament cords (13) in anamount of 5% to 50% of the fill cords (11).
 2. An improved belting (1)as set forth in claim 1 wherein the at least one fabric ply (2, 3, or 4)has a monofilament cord fill frequency in the range of one cord (13)every other fill location (11) to one cord (13) every twelfth filllocation (11).
 3. An improved belting (1) as set forth in claim 1wherein the at least one fabric ply (2, 3, or 4) has a monofilament cordfill frequency of one cord (13) every other fill location (11).
 4. Animproved belting (1) as set forth in claim 1 wherein the belt (1) iscomprised of two plies of the fabric (2, 3, or 4) having monofilamentcords (13) in an amount not more than 50% of the fill cords (11).
 5. Animproved belting (1) as set forth in claim 4 wherein the two fabricplies (2, 3, or 4) each have a monofilament cord fill frequency in therange of one cord (13) every other fill location (11) to one cord (13)every twelfth fill location (11).
 6. An improved belting (1) as setforth in claim 5 wherein the two fabric plies (2, 3, or 4) havediffering fill frequency of the monofilament cords (13) in the first andsecond fabric plies (2, 3, or 4).
 7. An improved multiple ply belting(1), comprising a center fabric ply (4), a first (2) and second (3)fabric plies disposed on opposite sides of the center fabric ply (4),the first (2) and second (3) fabric plies having fill cords (11)extending in the transverse direction of the belting (1), and aplurality of rubber layers (5, 6, 7, and 8) disposed on opposite sidesof the first and second fabric plies, the belting (1) beingcharacterized by: the first (2) and second (3) fabric plies havingmonofilament fill cords (13) in an amount 5% to 50% of the fill cords(11).
 8. An improved belting (1) as set forth in claim 7 wherein thefirst (2) and second (3) fabric plies have a monofilament cord fillfrequency in the range of one cord (13) every other fill location (11)to one cord (13) every twelfth fill location (11).
 9. An improvedbelting (1) as set forth in claim 7 wherein the first (2) and second (3)fabric plies have a monofilament cord fill frequency of one cord (13)every other fill location (11).
 10. An improved belting (1) as set forthin claim 7 wherein the first (2) and second (3) fabric plies havediffering fill frequency of the monofilament cords (13).